facebook/mms-1b-all with the pretrained lin adapter and CTC head, fine-tuned on WAXAL Lingala. Fresh single linear schedule (not a resume), batch 8 x accum 4 = 32 effective, lr 3e-5 body / 3e-4 head, warmup 400, 8 speakers held out.

Zero-shot baseline on the speaker-disjoint holdout: 0.8438 (WER 0.2301 / CER 0.0823).

The v3 lineage decoded with an AfriVoice 5-gram KenLM at alpha 0.3 / beta 0.5, beam 100, worth +0.0079 on the Zindi Lingala probe.

Reference points: v3 (~4 epochs, +KenLM) probes 0.289448; the best submission combining it with AF51 ck1200 on Shona scores 0.749367. Screen checkpoints by probe, not by the local eval curve -- that curve has pointed the wrong way three times in this competition.